JP6420117B2 - Biological information acquisition apparatus, wristwatch terminal, and biological information acquisition method - Google Patents

Description

  The present invention relates to a biological information acquisition device, a wristwatch terminal, and a biological information acquisition method, and more particularly to a biological information acquisition device that derives a pulse wave of a biological body based on a detection signal obtained by irradiating light on the biological body, a wristwatch terminal, and biological information acquisition. Regarding the method.

  When a living body is irradiated with light of a predetermined wavelength, the light is scattered (reflected / transmitted) by the epidermis, dermis surface, peripheral blood vessels, fat, arteries, etc. of the living body. Since the blood vessel pulse periodically moves within a predetermined time, the corresponding periodic motion can be observed from the obtained reflected light or transmitted light that passes through the living body. Therefore, in recent years, pulse waves have been measured by analyzing such reflected light and transmitted light.

  Here, in Patent Document 1, in order to remove body motion noise, light with a wavelength shorter than that of near-infrared light is applied to a living body from a detection signal of the amount of light reflected by a blood vessel obtained by irradiating the living body with near-infrared light. A technique for deriving a pulse wave by reducing a detection signal of the amount of reflected light on the skin surface obtained by irradiation is disclosed.

JP 2002-369805 A

  Although the technique of patent document 1 is devised so that body movement noise can be removed, body movement noise is only 4 to 5% of the whole noise added to a pulse wave, and body movement noise is removed. However, the accuracy of pulse wave measurement cannot be greatly improved.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a biological information acquisition device, a wristwatch terminal, and a biological information acquisition method capable of measuring pulse waves with high accuracy. .

A biological information acquisition apparatus according to an aspect of the present invention is provided.
A first detector that irradiates a living body with light of a first wavelength and detects reflected light or transmitted light from the living body;
A second detector for irradiating the living body with light of a second wavelength to detect reflected light or transmitted light from the living body;
The pulse wave of the living body based on a subtraction value obtained by subtracting the detection signal obtained by irradiating the living body with light of the second wavelength from the detection signal obtained by irradiating the living body with light of the first wavelength. A processing unit for deriving
Is provided.

A biological information acquisition method according to an aspect of the present invention includes:
Irradiating a living body with light of a first wavelength to detect reflected light or transmitted light from the living body;
Irradiating the living body with light of a second wavelength to detect reflected light or transmitted light from the living body;
The pulse wave of the living body based on a subtraction value obtained by subtracting the detection signal obtained by irradiating the living body with light of the second wavelength from the detection signal obtained by irradiating the living body with light of the first wavelength. Steps to derive
Is provided.

A biological information acquisition apparatus according to an aspect of the present invention is provided.
A substrate,
Either one of a light source and a light receiver provided on the substrate;
A plurality of other light sources or light receivers provided on the substrate, each disposed at least one on a substantially concentric circle of two or more around the light source or the light receiver;
A processing unit for deriving a pulse wave of the living body based on a detection signal of reflected light or transmitted light from the living body received by the light receiver;
Is provided.

  As described above, according to the present invention, it is possible to provide a biological information acquisition device, a wristwatch terminal, and a biological information acquisition method that can accurately measure a pulse wave.

It is a block diagram showing typically the living body information acquisition device of a 1st embodiment. It is a top view which shows typically the sensor unit in the biometric information acquisition apparatus of 1st Embodiment. It is a figure which shows typically a mode that the light radiate | emitted from the light source in the biometric information acquisition apparatus of 1st Embodiment is received with a light receiver via a biological body. It is a flowchart figure which shows the biometric information acquisition method of 1st Embodiment. It is a figure which shows the light emission timing of red light or infrared light, and green light. It is a figure which shows the light emission timing from which red light or infrared light differs from green light. It is a figure which shows the detection signal of the 1st detection part input into a processing apparatus as an example. It is a figure which shows an example of the waveform of the subtraction value which subtracted the detection signal of the 2nd detection part from the detection signal of the 1st detection part, and shows an example of the feature point extracted from a subtraction value and a subtraction value. It is a figure for deriving the blood pressure of a living body based on extracted feature points and a regression line. It is a figure which shows typically the sensor unit of 2nd Embodiment. It is a figure which shows typically the sensor unit of 3rd Embodiment. It is a figure which shows typically the sensor unit of 4th Embodiment. It is a figure which shows typically the sensor unit of 5th Embodiment. It is a figure which shows typically the sensor unit of 6th Embodiment. It is a figure which shows typically the sensor unit made into the structure which can detect the contact pressure to the biological body of a 1st light source. It is a figure which shows typically the structure which can adjust the contact pressure to the biological body of a 1st light source to the preset value.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

<First Embodiment>
First, the biological information acquisition apparatus and biological information acquisition method of this embodiment will be schematically described. The biological information acquisition apparatus and the biological information acquisition method of the present embodiment use a detection signal (that is, an output waveform) of reflected light or transmitted light from a blood vessel obtained by irradiating the living body with light of the first wavelength. A pulse wave of the living body is obtained based on a subtraction value obtained by irradiating the living body with light having a wavelength of 2 and subtracting a detection signal of reflected light or transmitted light in the vicinity of the dermis that is large as noise. As a result, a detection signal with less noise can be obtained, and the pulse wave of the living body and thus the blood pressure of the living body can be measured with high accuracy.

  Next, the biological information acquisition apparatus of this embodiment will be described in detail. FIG. 1 is a block diagram schematically showing a biological information acquisition apparatus according to the present embodiment. FIG. 2 is a plan view schematically showing a sensor unit in the biological information acquisition apparatus of the present embodiment. FIG. 3 is a diagram schematically illustrating a state in which light emitted from the light source in the biological information acquisition apparatus according to the present embodiment is received by the light receiver via the living body.

  The biometric information acquisition apparatus 1 is a biometric information acquisition apparatus provided in a wearable terminal, for example, and is worn on a wrist or the like. As shown in FIG. 1, the biological information acquisition apparatus 1 includes a sensor unit 10, an AFE (Analog Front End) 20, a processing device 30, and a display unit 40.

  The sensor unit 10 includes a first detection unit 11 and a second detection unit 12 and operates based on a control signal from the processing device 30. The first detection unit 11 receives a light source that emits red light or infrared light (IR: for example, a wavelength of 780 nm or more and 1100 nm or less) as detection light, and light reflected or transmitted by the detection light in the living body. It has a light receiver.

  The second detection unit 12 includes a light source that emits green light (for example, a wavelength of 495 nm or more and 570 nm or less) as detection light and a light receiver that receives light reflected or transmitted through the living body. .

  As light sources of the first detection unit 11 and the second detection unit 12, for example, light emitting elements such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes) can be used. As the light receivers of the first detection unit 11 and the second detection unit 12, a light receiving element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor image sensor (CMOS) can be used. The light receiver photoelectrically converts a signal indicating the intensity of the received light and outputs the signal to the AFE 20.

  The sensor unit 10 according to the present embodiment receives reflected light reflected by a blood vessel by irradiating the living body with red light or infrared light in the first detection unit 11, and receives green light in the second detection unit 12. The reflected light reflected by peripheral blood vessels and fats near the dermis is received.

  Specifically, as shown in FIG. 2, the sensor unit 10 includes a first light source 111 that emits red light or infrared light as detection light on a common substrate 13, and a second light source that emits green light as detection light. , A third light source 122 that emits green light as detection light, and a light receiver 112. That is, the sensor unit 10 of the present embodiment includes one first detection unit 11 and two second detection units 12, and the first light receiver of the two second detection units 12 is the first. The light receiver 112 of the detection unit 11 is commonly used. Thereby, the number of light receivers 112 can be reduced, and the sensor unit 10 can be reduced in size.

  Here, the distance between the light receiver and the light source generally corresponds to the depth of penetration of light into the living body. Therefore, in the present embodiment, as shown in FIG. 3, the third light source 122, the second light source 121, and the first light source 111 are arranged in this order in the direction away from the light receiver 112, so The first light source 111 used for obtaining the reflected light of the blood vessel existing inside is disposed at a position farther from the light receiver 112 than the second light source 121 and the third light source 122. Thereby, the reflected light in the blood vessel can be received well. Incidentally, in FIG. 3, the light irradiation area is shown by hatching. The intervals between the light sources 111, 121, and 122 are appropriately set based on the wavelength of the emitted light.

  Moreover, the 1st light source 111 of this Embodiment, the 2nd light source 121, and the 3rd light source 122 are arrange | positioned at the substantially equal space | interval on a substantially straight line, as shown in FIG. Thereby, when the biological information acquisition apparatus 1 is mounted on a living body, the first light source 111, the second light source 121, and the third light source 122 can be arranged on substantially equal blood vessels, and the measurement accuracy of pulse waves Can be improved.

  The AFE 20 includes an amplifier 21, a noise removal filter 22, and an ADC (Analog Digital Converter) 23. The amplifier 21 amplifies the detection signal from the sensor unit 10. The noise removal filter 22 is an analog filter and removes noise of the detection signal amplified by the amplifier 21 by analog processing. For example, the noise removal filter 22 is an LC filter such as a low-pass filter or a high-pass filter.

  The ADC 23 converts the detection signal from which noise has been removed by the noise removal filter 22 into a digital signal. Then, the ADC 23 outputs the detection signal converted into the digital signal to the processing device 30. The ADC 23 outputs a digital value sampled at a predetermined sampling period as a detection signal.

  The processing device 30 is, for example, a microcomputer, and includes a CPU (Central Processing Unit) 31, a memory 32, a digital filter 33, and a power management unit 34. The memory 32 stores a predetermined program. The CPU 31 reads and executes a program stored in the memory 32. By doing so, the processing device 30 measures blood pressure (SBP, DBP) and the like based on the detection signal from the AFE 20, and outputs a signal indicating the measured blood pressure and the like to the display unit 40. In addition, you may make it the processing apparatus 30 measure health indexes other than blood pressure, for example, AI (arteriosclerosis index) value.

  The digital filter 33 subtracts the detection signal obtained by irradiating the living body with the detection light from the second light source 121 or the third light source 122 from the detection signal obtained by irradiating the living body with the detection light from the first light source 111. Process. Here, since the pulse wave corresponding to the pulsation of the blood vessel repeatedly appears in the detection signal, the pulse wave of the living body can be obtained based on the detection signal.

  The power management unit 34 controls the power supplied to the sensor unit 10. For example, the power management unit 34 supplies a predetermined drive current to each of the light sources 111, 121, and 122 to cause each of the light sources 111, 121, and 122 to emit light with a predetermined intensity. Furthermore, the power management unit 34 may control the timing of supplying current to each of the light sources 111, 121, and 122 so that each of the light sources 111, 121, and 122 emits light intermittently at a predetermined timing.

  The display unit 40 outputs information such as the pulse wave and blood pressure of the living body indicated in the signal from the processing device 30. As the display unit 40, for example, a liquid crystal display or an EL (Electro Luminescence) display can be used.

  Next, a biometric information acquisition method using the biometric information acquisition apparatus 1 described above will be described. In addition, the biological information acquisition method of this Embodiment measures a blood pressure based on the pulse wave of a biological body. Here, FIG. 4 is a flowchart showing the biometric information acquisition method of the present embodiment. FIG. 5 is a diagram illustrating light emission timings of red light or infrared light and green light. FIG. 6 is a diagram illustrating different emission timings of red light or infrared light and green light. FIG. 7 is a diagram exemplarily showing a detection signal of the first detection unit input to the processing apparatus. FIG. 8 is a diagram illustrating an example of a waveform of a subtraction value obtained by subtracting the detection signal of the second detection unit from the detection signal of the first detection unit, and a diagram illustrating an example of the subtraction value and a feature point extracted from the subtraction value. It is. FIG. 9 is a diagram for deriving the blood pressure of the living body based on the extracted feature points and the regression line.

  First, the biological information acquisition apparatus 1 is attached to the wrist of a living body using, for example, a bunt, and the detection light of the first light source 111, the second light source 121, and the third light source 122 is respectively applied to the living body as shown in FIG. The reflected light from the living body is received by the light receiver 112 (S1).

  Specifically, the first light source 111, the second light source 121, and the third light source 122 are controlled based on a control signal from the processing device 30 so that the light emission periods of the first light source 111, the second light source 121, and the third light source 122 do not overlap. The light source 121 and the third light source 122 emit light for a predetermined period with a predetermined cycle.

  In this embodiment, the pulse wave of the living body is sampled in advance, and as shown in FIG. 5, first, the first light source 111 is caused to emit light for substantially one period of the pulse wave, and then the second light source 121 is turned on. Similarly, light is emitted for substantially one period of the pulse wave. Further, the third light source 122 is caused to emit light for substantially one cycle period of the pulse wave.

  That is, the living body is irradiated with the first light source 111, the second light source 121, and the third light source 122 in order for each period of the pulse wave. Thereby, the living body can be irradiated with the first light source 111, the second light source 121, and the third light source 122 from the time when the intensity of the detection signal is approximately equal to the period of time that is approximately equal.

  However, the start point of one cycle may not be the minimum point of the pulse wave, and is not particularly limited. In the present embodiment, the first light source 111, the second light source 121, and the third light source 122 are each irradiated within the entire period of one cycle. For example, as shown in FIG. The detection light of the first light source 111, the second light source 121, and the third light source 122 may be emitted intermittently for an equal period with a period substantially equal to the pulse wave. Thereby, power consumption of the first light source 111, the second light source 121, and the third light source 122 can be suppressed. Further, the order of light emission of the light sources is not particularly limited, and it is sufficient that the light emission of the first light source 111, the second light source 121, and the third light source 122 is a set.

  As described above, red light and infrared light are reflected by blood vessels, and green light is reflected by peripheral blood vessels and fats near the dermis. Therefore, as shown in FIG. 3, the detection light irradiated on the living body from the first light source 111 is reflected by the blood vessel, and the reflected light is received by the light receiver 112. Further, the detection light irradiated on the living body from the second light source 121 is reflected by peripheral blood vessels or fats near the dermis, and the reflected light is received by the light receiver 112. Further, the detection light irradiated on the living body from the third light source 122 is reflected by peripheral blood vessels or fats near the dermis, and the reflected light is received by the light receiver 112. The light receiver 112 photoelectrically converts a signal indicating the intensity of the received light and outputs an analog signal to the AFE 20.

  Next, the AFE 20 processes the detection signal input from the sensor unit 10 (S2). Specifically, the amplifier 21 of the AFE 20 amplifies the detection signal input from the sensor unit 10 based on the control signal of the processing device 30. The noise removal filter 22 of the AFE 20 removes noise by filtering the amplified detection signal based on the control signal of the processing device 30. Further, the ADC 23 of the AFE 20 digitally processes the detection signal from which noise has been removed based on the control signal of the processing device 30, and outputs the digitally processed detection signal to the processing device 30. For example, the ADC 23 of the AFE 20 outputs the detection signal of the first detection unit 11 having a waveform as shown in FIG.

  Next, the processing device 30 measures the blood pressure based on the detection signal input from the AFE 20 (S3). Between the epidermis and blood vessels, there are peripheral blood vessels and fats near the dermis, and noise based on reflected light reflected by such peripheral blood vessels and fats causes detection light from the first light source 111 to enter the living body. It is included in the detection signal of the reflected light obtained by irradiation.

  Therefore, the digital filter 33 of the processing device 30 converts the detection light from the second light source 121 or the third light source 122 from the reflected light detection signal obtained by irradiating the detection light from the first light source 111 to the living A pulse wave of the living body is obtained based on a subtraction value obtained by subtracting the detection signal of the reflected light obtained by irradiating the light. Then, the digital filter 33 outputs a detection signal indicating a subtraction value (that is, a detection signal indicating a biological pulse wave) to the CPU 31.

  As a result, it is possible to obtain a detection signal in which noise caused by reflection of the detection light by peripheral blood vessels or fats near the dermis is satisfactorily removed, and as a result, it is possible to improve the measurement accuracy of the pulse wave of the living body. it can.

  In addition, from the detection signal of the reflected light obtained by irradiating the living body with the detection light from the first light source 111, the reflected light obtained by irradiating the living body with the detection light from the second light source 121 or the third light source 122 is used. Since this is a simple process for reducing the detection signal, the processing load on the processing device 30 can be reduced.

  Here, in the present embodiment, a detection signal of reflected light obtained by irradiating the living body with detection light from the second light source 121 and reflected light obtained by irradiating the living body with detection light from the third light source 122. Is selected from the detection signals of the reflected light obtained by irradiating the living body with the detection light from the first light source 111. Thereby, the pulse wave of a living body can be measured with higher accuracy.

  Next, the CPU 31 of the processing device 30 measures the blood pressure based on the detection signal input from the digital filter 33. Specifically, as shown in FIG. 8, the CPU 31 detects from the second light source 121 or the third light source 122 from the reflected light detection signal obtained by irradiating the living body with the detection light from the first light source 111. One period of the pulse wave is specified from a period in which the subtracted value obtained by subtracting the detection signal of the reflected light obtained by irradiating the living body with light is positive. In the following description, a pulse wave for one cycle is referred to as a single pulse wave. The CPU 31 sets the timing at which the subtraction value changes from negative to positive as the starting point of one pulse wave. Incidentally, in FIG. 8, the pulse wave of the living body by the subtraction value is shown on the lower side, and a part of the pulse wave of the ideal living body is enlarged on the upper side.

  And CPU31 extracts the feature point of one pulse wave based on a subtraction value. The CPU 31 extracts, for example, a maximum value, a minimum value, a maximum value, a minimum value, an inflection point, and the like as feature points for each pulse wave. The CPU 31 calculates the value of the feature point and the time from the waveform of the subtraction value. For example, the CPU 31 calculates a feature point by differentiating the pulse wave to obtain a velocity pulse wave or obtaining an acceleration pulse wave by differentiating twice.

  In FIG. 8, the first peak (maximum value) in one cycle is the systolic peak, and the second peak (maximum value) is the reflective peak. Furthermore, the minimum value after the second peak is a notch indicating the boundary between systolic and diastolic phases. The time from the start point of one cycle to the systolic peak is defined as S.P. Time. From the start point of one cycle, R.E. Time. The time from the start point of one cycle to the notch is defined as Notch Time. Further, the CPU 31 extracts a minimum value of one cycle as a feature point. Thus, the CPU 31 calculates values and times at a plurality of feature points. In the present embodiment, the maximum value, the minimum value, etc. may be corrected based on the subtraction value at the notch.

  CPU31 calculates a feature-value from the value of several feature points contained in one pulse wave, and time. In this specification, the feature amount is a value for calculating blood pressure (SBP, DBP), and is a value derived from the value of a feature point in one pulse wave and time. The feature amount can be calculated based on a preset calculation formula.

  Then, the CPU 31 converts the feature amount into blood pressure. CPU31 converts a feature-value into a blood-pressure value using a regression line. Here, as shown in FIG. 9, two regression lines are stored in the memory 32 in order to calculate SBP (systolic blood pressure: BP_MAX) and BP (diastolic blood pressure: BP_MIN). Then, the CPU 31 calculates a feature quantity for SBP and a feature quantity for DBP based on the single pulse wave. And CPU31 calculates SBP and DBP from two feature-values using a regression line, respectively. In this way, the processing device 30 derives the blood pressure and outputs a signal indicating the blood pressure to the display unit 40. Incidentally, in FIG. 9, a diagram for calculating BP_MAX is shown on the right side, and a diagram for calculating BP_MIN is shown on the left side.

  The regression line is set using a plurality of measurement results acquired in advance. That is, for a plurality of measurement subjects, a feature amount is obtained by the biological information acquisition apparatus according to the present embodiment, and a blood pressure value is measured by a conventional cuff sphygmomanometer. Thereby, the database which matched the feature-value and blood-pressure value is constructed | assembled. Then, regression analysis is performed on the data stored in the database to obtain a regression line.

  Here, the regression line may be set according to sex and age. For example, it may be set for each gender and age group, such as a male in his 20s, a female in his 20s, a male in his 30s and a female in his 30s. That is, data may be acquired for each age and sex to construct a database.

  In addition, the CPU 31 may convert the feature amount into blood pressure using a regression curve using not only the regression line but also a quadratic or higher polynomial.

  Further, the CPU 31 may calculate the blood pressure based on a plurality of pulse waves. For example, the CPU 31 extracts feature points for each of n (n is an integer of 2 or more) pulse waves, and calculates a feature amount. Thereby, since the feature amount is calculated for each pulse wave, n feature amounts are calculated. Then, the CPU 31 converts the n feature amounts into blood pressure (SBP or DBP) using the regression line. Thereby, n blood pressure values are calculated. The average value of the n blood pressure values can be used as the blood pressure. Thus, measurement accuracy can be improved by calculating feature quantities based on a plurality of pulse waves.

  Further, the blood pressure may be obtained by removing the maximum value or the minimum value of the n blood pressure values. For example, an average value of (n−2) blood pressure values excluding the maximum value and the minimum value among the n blood pressure values may be used as the blood pressure. Thereby, the measurement accuracy can be further improved.

  Note that one pulse wave (one cycle) for which a feature point cannot be extracted may be excluded from the calculation of blood pressure. For example, when the maximum value and the minimum value necessary for calculating the feature value are buried in noise due to the influence of noise or the like and cannot be calculated, the feature value cannot be calculated for that period. Therefore, it is preferable not to convert the blood pressure for one pulse wave (one cycle) from which feature points cannot be extracted. In this way, blood pressure measurement accuracy can be improved.

  In this way, the CPU 31 estimates the tendency of the pulse wave to rise and fall based on the subtraction value, and estimates the maximum value, the minimum value, the maximum value, the minimum value, the inflection point, and the like as feature points. Then, the CPU 31 calculates a feature amount from a plurality of feature points for each pulse wave, and converts the feature amount into a blood pressure value using a regression line obtained in advance by the database.

  Next, the display unit 40 outputs the blood pressure indicated by the signal input from the processing device 30 (S4).

  As described above, in the present embodiment, the light of the second wavelength is obtained by irradiating the living body with the light of the second wavelength from the detection signal of the reflected light or transmitted light from the blood vessel obtained by irradiating the living body with the light of the first wavelength. A pulse wave of a living body is obtained based on a subtraction value obtained by subtracting a detection signal of reflected light or transmitted light in the vicinity of the dermis that is large as noise. Therefore, a detection signal with less noise can be obtained, and the pulse wave of the living body, and thus the blood pressure of the living body can be accurately measured.

<Second Embodiment>
In the present embodiment, different forms of the sensor unit will be described. FIG. 10 is a diagram schematically showing the sensor unit of the present embodiment. Note that the same elements as those in the biological information acquisition apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant descriptions will be omitted.

  As shown in FIG. 10, the sensor unit 50 of the present embodiment includes a light source unit 51 in which a first light source 111, a second light source 121, and a third light source 122 are arranged on a substantially straight line on a substrate 13. The light receivers 112 are arranged radially around the center. The light sources 111, 121, and 122 of each light source unit 51 are arranged on different substantially concentric circles.

  That is, the first light source 111 of each light source unit 51 is arranged on the first circle centered on the light receiver 112. The second light source 121 of each light source unit 51 is disposed on a second circle having a smaller diameter than the first circle around the light receiver 112. The third light source 122 of each light source unit 51 is disposed on a third circle smaller than the second circle with the light receiver 112 as the center.

  The waveform of the pulse wave to be measured varies depending on how the biological information acquisition apparatus is attached to the living body (for example, whether it is in contact with or away from the living body, or what is the pressure). Therefore, among the light source units 51, the processing device 30 selects a light source unit 51 that satisfies a predetermined condition (for example, the light sources 111, 121, and 122 are in contact with the living body at a predetermined pressure), and the selected light source unit 51 is selected. If a pulse wave of a living body is obtained based on a detection signal obtained by irradiating the living body with detection light from each of the light sources 111, 121, and 122, the pulse wave can be measured with high accuracy.

  The sensor unit 50 of the present embodiment subtracts the detection signal obtained by irradiating the living body with green light as the detection light from the detection signal obtained by irradiating the living body with red light or infrared light as the detection light. Although it is a structure premised on performing a process, when noise is not removed using the detection signal obtained by irradiating a living body with green light as detection light, all the light sources mounted in the sensor unit 50 are the first. The light source 111 can be configured. At this time, the interval between the first light sources adjacent in the radial direction and the interval between the first light sources adjacent in the circumferential direction are appropriately set based on the wavelength of the emitted light.

  In this case, the detection signal obtained by irradiating the living body with the detection light from all the first light sources 111 is sampled, and the best signal state is obtained by irradiating the living body with the detection light from the first light source 111 ( For example, a pulse wave of a living body is obtained based on a detection signal (which makes it easy to extract feature points). Thereby, the pulse wave of a living body can be measured with high accuracy. That is, the detection signal having the best signal state among the plurality of first light sources 111 arranged on the straight line and the best signal state among the plurality of first light sources 111 arranged on the same circle is obtained. A first light source 111 that can be obtained is selected, and a pulse wave of the living body is obtained based on a detection signal obtained by irradiating the living body with detection light from the first light source 111.

  In addition, when the database is created by collecting data with the distance between the first light source 111 and the light receiver 112 being constant, the first database is created as described above. If the light sources 111 are arranged on substantially concentric circles, the distance from the first light source 111 arranged on the substantially same circle to the light receiver 112 is substantially equal, so that an error in the blood pressure estimation algorithm by the database can be suppressed.

  In addition, as compared with the case where the first light sources 111 are arranged in a matrix on the substrate 13, the number of the first light sources 111 can be reduced by arranging the first light sources 111 on a substantially concentric circle as described above. As a result, it is possible to contribute to weight reduction of the biological information acquisition apparatus.

  Incidentally, Patent Document 2 (Japanese Patent No. 2766317) discloses a configuration in which light emitting elements are arranged on a circle centered on a light receiving element, which is a technique related to measurement of oxygen saturation in blood.

<Third Embodiment>
Different forms of the sensor unit will be described when noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light. FIG. 11 is a diagram schematically showing the sensor unit of the present embodiment. Note that the same elements as those in the biological information acquisition apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant descriptions will be omitted.

  In the sensor unit 60 of the present embodiment, as shown in FIG. 11, the light receiver unit 61 in which a plurality of light receivers 112 are arranged on a substantially straight line is radially formed on the substrate 13 with the first light source 111 as the center. Has been placed. The light receivers 112 of the respective light receiver units 61 are arranged on different substantially concentric circles. At this time, the interval between the optical receivers 112 adjacent to each other in the radial direction and the interval between the optical receivers 112 adjacent to each other in the circumferential direction are appropriately set based on the wavelength of the emitted light from the first light source 111.

  As described above, since the waveform of the pulse wave to be measured varies depending on how the biological information acquisition device is attached to the living body, among the light receivers 112, a predetermined condition is satisfied (for example, the living body is contacted with a predetermined pressure). ) By selecting the light receiver 112 and obtaining a pulse wave of the living body based on the detection signal of the selected light receiver 112, the measurement accuracy of the pulse wave can be improved.

  Further, when the data is collected by creating a database as described above by classifying by sex, age, weight, etc., and collecting the data with the distance between the first light source 111 and the light receiver 112 being constant, the light receiver 112 as described above. Are arranged on substantially concentric circles, the light receivers 112 on the same substantially circular circle have a substantially constant distance to the first light source 111, so that an error in the blood pressure estimation algorithm by the database can be suppressed.

  Moreover, as compared with the case where the light receivers 112 are arranged in a matrix on the substrate 13, the number of the light receivers 112 can be reduced if the light receivers 112 are arranged substantially concentrically as described above. This can contribute to weight reduction of the biological information acquisition device.

<Fourth embodiment>
Different forms of the sensor unit will be described when noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light. FIG. 12 is a diagram schematically showing the sensor unit of the present embodiment. Note that the same elements as those in the biological information acquisition apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant descriptions will be omitted.

  As shown in FIG. 12, the sensor unit 70 of the present embodiment has a light receiver 112 on a substrate 13 on a substantially spiral line (indicated by a two-dot chain line in FIG. 12) around the first light source 111. Has been placed. Also in this case, by selecting a light receiver 112 that satisfies a predetermined condition from among the plurality of light receivers 112 and obtaining a pulse wave of a living body based on the detection signal of the selected light receiver 112, the measurement accuracy of the pulse wave is increased. Can be improved. At this time, the interval between the adjacent light receivers 112 on the spiral is appropriately set based on the wavelength of the emitted light from the first light source 111 and the like.

  In the present embodiment, the light receiver 112 is arranged on a substantially spiral line with the first light source 111 as the center, but the first light source 111 is arranged on the substantially spiral line with the light receiver 112 as a center, A first light source 111 that satisfies a condition may be selected, and a pulse wave of the living body may be obtained based on a detection signal of reflected light obtained by irradiating the living body with detection light from the selected first light source 111.

<Fifth embodiment>
Different forms of the sensor unit will be described when noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light. FIG. 13 is a diagram schematically showing the sensor unit of the present embodiment. Note that the same elements as those in the biological information acquisition apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant descriptions will be omitted.

  As shown in FIG. 13, in the sensor unit 80 of the present embodiment, a plurality of first light sources 111 and light receivers 112 are arranged on a substrate 13 on a substantially straight line. Also in this case, by selecting the first light source 111 that satisfies the predetermined condition from the plurality of first light sources 111 and obtaining the pulse wave of the living body based on the detection signal of the selected first light source 111, The measurement accuracy of the pulse wave can be improved.

  In the present embodiment, the plurality of first light sources 111 and the light receivers 112 are arranged on a substantially straight line, but the first light source and the plurality of light receivers 112 are arranged on a substantially straight line, and predetermined conditions are satisfied. It is also possible to select a photoreceiver 112 that satisfies the condition, and obtain a pulse wave of the living body based on a detection signal obtained by irradiating the living body with detection light from the selected photoreceiver 112.

<Sixth Embodiment>
Different forms of the sensor unit will be described when noise is not removed using a detection signal obtained by irradiating a living body with green light as detection light. FIG. 14 is a diagram schematically showing the sensor unit of the present embodiment. Note that the same elements as those in the biological information acquisition apparatus 1 of the first embodiment will be described using the same reference numerals, and redundant descriptions will be omitted.

  In the sensor unit 90 of the present embodiment, as shown in FIG. 14, a plurality of ring-shaped light sources 91 having different diameters are arranged on the substrate 13 around the light receiver 112. Also in this case, a detection signal obtained by selecting a light source 91 satisfying a predetermined condition (for example, contacting the living body with a predetermined pressure) among the light sources 91 and irradiating the living body with detection light from the selected light source 91. By obtaining the pulse wave of the living body based on the above, the measurement accuracy of the pulse wave can be improved. Here, the interval between the adjacent light sources 91 is appropriately set based on the wavelength of the emitted light.

  In the present embodiment, the ring-shaped light source 91 is disposed around the light receiver 112, but a plurality of ring-shaped light receivers are disposed around the point light source, and a light receiver that satisfies a predetermined condition is selected. The pulse wave of the living body may be measured based on the detection signal of the selected light receiver.

<Seventh embodiment>
The substrate 13 is preferably composed of a flexible substrate. Thereby, the light source and the light receiver can be satisfactorily brought into contact with the living body by causing the substrate 13 to follow the curvature of the wrist of the living body, for example.

  Thus, when the biological information acquisition apparatus which comprised the board | substrate 13 with the flexible board | substrate was mounted | worn with the biological body, the board | substrate 13 will curve and the above-mentioned concentric circle will deform | transform. Therefore, in a state where the biological information acquisition device is attached to the living body, either the light source or the light receiver is centered on the other while the substrate 13 is flat so that the light source or the light receiver is arranged on a substantially concentric circle. It is preferable to arrange on a concentric ellipse. Thereby, when creating the database, the distance between the first light source 111 and the light receiver 112 can be made constant with high accuracy.

<Eighth Embodiment>
As described above, when detecting the contact pressure of the light source or the light receiver to the living body, the following configuration may be employed. FIG. 15 is a diagram schematically showing a sensor unit configured to detect the contact pressure of the first light source to the living body.

  As shown in FIG. 15, the sensor unit of the present embodiment includes a pressure detection unit 14 between the first light source 111 and the substrate 13. As the pressure detection unit 14, a general pressure sensor can be used.

  When such a configuration is employed in, for example, a sensor unit including a plurality of first light sources 111, the processing device is set in advance among the plurality of first light sources 111 based on the detection signal of the pressure detection unit 14. A first light source 111 having a pressure value or higher is selected, and a pulse wave of the living body is obtained based on a detection signal obtained by irradiating the living body with detection light from the selected first light source 111. Thereby, the measurement difficulty by the dispersion | variation in the mounting state to the biological body of a biometric information acquisition apparatus or the individual difference of a biological body can be avoided.

  However, in FIG. 15, although it is set as the structure which can detect the contact pressure to the biological body of the 1st light source 111, in the case of a sensor unit provided with the some light receiver 112, for example, each light receiver 112 and a board | substrate What is necessary is just to arrange | position the pressure detection part 14 between.

<Ninth embodiment>
Here, it is preferable that the contact pressure of the light source or the light receiver to the living body can be adjusted to a preset value. FIG. 16 is a diagram schematically illustrating a configuration in which the contact pressure of the first light source to the living body can be adjusted to a preset value.

  In the present embodiment, as shown in FIG. 16, a pressure detection unit 14 and a pressure adjustment unit 15 are provided between the first light source 111 and the substrate 13. For example, an actuator can be used as the pressure adjusting unit 15.

  When such a configuration is employed in, for example, a sensor unit including a plurality of first light sources 111, the processing device controls the pressure adjustment unit 15 based on the detection signal from the pressure detection unit 14, and the first light source 111. The contact pressure to the living body is adjusted to a preset value. Then, the processing device generates a pulse wave of the living body based on the detection signal with the best signal state (for example, easy to extract feature points) obtained by irradiating the living body with detection light from the plurality of first light sources 111. obtain. Thereby, the measurement difficulty by the dispersion | variation in the mounting state to the biological body of a biometric information acquisition apparatus or the individual difference of a biological body can be avoided.

  However, in FIG. 16, the contact pressure of the first light source 111 to the living body can be adjusted. For example, in the case of a sensor unit including a plurality of light receivers 112, each light receiver 112 and the substrate 13 What is necessary is just to arrange | position the pressure detection part 14 and the pressure adjustment part 15 between these.

<Tenth Embodiment>
When a sensor unit including a plurality of first light sources 111 or a plurality of light receivers 112 is used, a plurality of other first light sources 111 having different distances from one of the central first light source 111 and the light receiver 112 are used. Alternatively, the blood pressure of the living body may be derived by a general PWTT (Pulse Wave Transit Time) method based on pulse waves obtained at different positions of the living body by operating the light receiver 112.

<Eleventh embodiment>
When the sensor unit includes a plurality of first light sources 111, it is preferable to change the frequency of the emitted light of the first light source according to the distance from the light receiver 112. For example, the frequency of the emitted light from the first light source 111 is increased as the distance from the light receiver 112 increases. Thereby, the depth of penetration of the emitted light of the first light source 111 into the living body can be adjusted.

  The embodiments of the biometric information acquisition apparatus and the biometric information acquisition method according to the present invention have been described above. However, the present invention is not limited to the above, and can be changed without departing from the technical idea of the present invention.

  For example, in the above embodiment, the pulse wave of the living body is measured based on the reflected light that the detection light is reflected in the living body, but the pulse wave of the living body is based on the transmitted light that is transmitted through the living body. May be measured. In this case, what is necessary is just to arrange | position a light source and a light receiver so that a biological body may be arrange | positioned between a light source and a light receiver.

  For example, in the second and subsequent embodiments, the sensor unit including a plurality of the first light sources 111 or the light receivers 112 has been described. However, the present invention is not limited to the above-described configuration. That is, the plurality of first light sources 111 or light receivers 112 may be arranged on the substrate 13 irregularly or regularly.

  For example, the biometric information acquisition apparatus of the above embodiment can be incorporated into a wearable terminal such as a wristwatch terminal. That is, it can also be regarded as a wristwatch terminal equipped with a biological information acquisition device. Furthermore, the sensor unit 10 is provided in the wristwatch terminal and has a wireless communication unit, and other configurations (for example, the processing device 30 and the display unit 40) may be provided in the smartphone. In this case, analog data or digital data acquired by the wristwatch terminal is transferred to the smartphone by wireless communication. And the smart phone which received data may perform a part or all of the process for measuring a blood pressure.

DESCRIPTION OF SYMBOLS 1 Biological information acquisition apparatus 10 Sensor unit 11 1st detection part, 111 1st light source, 112 Light receiver 12 2nd detection part, 121 2nd light source, 122 3rd light source 13 Board | substrate 14 Pressure detection part 15 Pressure Adjustment unit 20 AFE, 21 amplifier, 22 noise removal filter, 23 ADC
30 processing device, 31 filter, 32 memory, 33 digital filter, 34 power management unit 40 display unit 50 sensor unit, 51 light source unit 60 sensor unit, 61 light receiver unit 70 sensor unit 80 sensor unit 90 sensor unit, 91 light source

Claims (3)

A first detector that irradiates a living body with light of a first wavelength and detects reflected light or transmitted light from the living body;
A second detector that irradiates the living body with light of a second wavelength that is not less than 495 nm and not more than 570 nm to detect reflected light or transmitted light from the living body;
The pulse wave of the living body based on a subtraction value obtained by subtracting the detection signal obtained by irradiating the living body with light of the second wavelength from the detection signal obtained by irradiating the living body with light of the first wavelength. A processing unit for deriving
Equipped with a,
The irradiation of the light of the first wavelength to the living body and the irradiation of the light of the second wavelength to the living body are set in advance so as to be substantially equal to the period of the pulse wave of the living body so that the irradiation periods do not overlap. The biometric information acquisition apparatus which performs in a substantially equal period with a given period . A wristwatch terminal comprising the biological information acquisition device according to claim 1 . Irradiating a living body with light of a first wavelength to detect reflected light or transmitted light from the living body;
Irradiating the living body with light of a second wavelength that is not less than 495 nm and not more than 570 nm to detect reflected light or transmitted light in the living body;
The pulse wave of the living body based on a subtraction value obtained by subtracting the detection signal obtained by irradiating the living body with light of the second wavelength from the detection signal obtained by irradiating the living body with light of the first wavelength. Steps to derive
Equipped with a,
The irradiation of the light of the first wavelength to the living body and the irradiation of the light of the second wavelength to the living body are set in advance so as to be substantially equal to the period of the pulse wave of the living body so that the irradiation periods do not overlap. A biological information acquisition method that is performed in a substantially equal period in a given cycle .